JP2012501518A - Electrolyte-containing polymer produced by electrospinning process and highly efficient dye-sensitized solar cell using the electrolyte-containing polymer - Google Patents

Abstract

The present invention relates to a polymer electrolyte comprising polymer fibers having a nanoscale diameter and manufactured by an electrospinning method. The present invention also relates to a solar cell element having a nanoscale diameter and using a polymer electrolyte containing polymer fibers produced by an electrospinning method and exhibiting high energy conversion efficiency. The solid state electrolyte containing the nano-sized polymer fiber of the present invention does not require an encapsulant and further simplifies the overall process compared to conventional dye-sensitized solar cells that use liquid electrolytes. In particular, the energy conversion efficiency of the dye-sensitized solar cell of the present invention is far superior to a dye-sensitized solar cell using a polymer thin film electrolyte produced by a spin coating method. Furthermore, this dye-sensitized solar cell can be obtained by using a scattering layer and compensating for surface effects.
[Selection] Figure 1

Description

  The present invention relates to a solar cell element, and more particularly to a polymer electrolyte having a nanoscale diameter and comprising polymer fibers produced by electrospinning a PVDF-HFP polymer. The present invention also relates to a high-performance dye-sensitized solar cell element using the polymer electrolyte.

  There are environmental problems such as global warming due to continuous use of fossil fuels. Further, the use of uranium causes problems such as radioactive contamination and the need for facilities to dispose of radioactive waste. Therefore, there is a strong demand for alternative energy, and various studies on alternative energy have been conducted. The surface type of alternative energy is solar energy.

  A solar cell element is an element that directly generates electricity by using a light-absorbing material that generates electrons and holes when irradiated with light. In 1839, a French physicist named Becquerel first discovered a photovoltaic that a light-induced chemical reaction produces an electric current. A similar phenomenon was found for solids such as selenium. Since then, much research on solar cells has continued in connection with inorganic silicones. This is because a silicon-based solar cell having an efficiency of about 6% was first developed in 1954 at the Bell Research Center.

  Such an inorganic solar cell element is composed of a pn junction of an inorganic semiconductor such as silicon. Silicon used in solar cells can be classified into crystalline silicon and amorphous silicon such as single crystal silicon or polycrystalline silicon. Crystalline silicone has better energy conversion efficiency compared to amorphous silicon when solar energy is converted to electrical energy. However, crystalline silicon is less productive due to the time and energy used to grow crystals. Amorphous silicone has excellent light absorbency, can be easily expanded, and has better productivity than crystalline silicon. However, amorphous silicon is inefficient in terms of equipment because, for example, a vacuum process or the like is required. Particularly, in the case of an inorganic solar cell element, there is a problem because it is difficult to process and mold the inorganic solar cell element. This is because the manufacturing cost is high and the device is manufactured under vacuum conditions.

  Due to such problems, various studies have been attempted on solar cell elements that use the photovoltaic phenomenon of organic materials (instead of silicone). Photovoltaic phenomenon of organic material means that when organic material is irradiated with light, the organic material absorbs photons to generate electron-hole pairs, which are separated from each other and transferred to the cathode and anode respectively. And then refers to the phenomenon in which current is generated by such charge flow. In other words, normally, in an organic solar cell, when light is irradiated to the junction between the electron donor material and the electron acceptor material, an electron-hole pair is formed in the electron donor, and the electron is an electron acceptor. To separate the electron-holes. Such a process is called “excitation of charge carriers by light” or “photoinduced charge transfer (PICT)”, where the carriers generated by light are divided into electron-holes and generate power through an external circuit. .

  When considering the basics of physics, the output power generated by all solar power generation, including solar cells, is considered to be the product resulting from the exciton flow and driving force of light-induced excitation generated by light. . In solar cells, flow is related to current and driving force is directly related to voltage. In general, the voltage of a solar cell is determined by the electrode material used, the solar energy conversion efficiency is a value obtained by dividing the output voltage by the input solar energy, and the total output current depends on the number of photons absorbed. Determined.

  An organic solar cell prepared by using the above-described optical pumping phenomenon of an organic material includes an electron donor layer and an electron acceptor layer introduced between a transparent electrode and a metal electrode. And a single-layer solar cell into which a mixture of electron acceptors is introduced.

  However, solar cells using typical organic materials have problems in terms of energy conversion efficiency and durability. In this regard, the Swiss Gratzel (Gr) research team developed a dye-sensitized solar cell, a photoelectrochemical solar cell, in 1991 by using a dye as a photosensitizer. The photoelectrochemical solar cell suggested by Gratzel et al. Uses an oxide semiconductor comprising nanoparticulate titanium dioxide and photosensitizing dye molecules. In other words, a dye-sensitized solar cell is prepared by introducing an electrolyte into an inorganic oxide layer such as titanium oxide, and the dye is absorbed between the transparent electrode and the metal electrode and undergoes a photoelectrochemical reaction. Solar cell. In general, a dye-sensitized solar cell includes two types of electrodes (photoelectrode and counter electrode), an inorganic oxide, a dye, and an electrolyte. The dye-sensitized solar cell is environmentally friendly because it uses a material that is not harmful to the environment and has a high energy conversion efficiency of about 10% after the amorphous silicon solar cell among the existing inorganic solar cells. Furthermore, its manufacturing cost is about 20% of silicon solar cells. Therefore, a high potential for commercialization was reported.

  As described above, a dye-sensitized solar cell manufactured by using a photochemical reaction is introduced with an inorganic oxide layer in which a dye that absorbs light is absorbed between an anode and a cathode, and electrons are absorbed. A multilayer battery element in which a reducing electrolyte layer is introduced. A conventional dye-sensitized solar cell element will be briefly described below.

  A conventional multilayer dye-sensitized solar cell may include, for example, a titanium oxide layer / electrolyte / electrode, and an electrode on which a substrate / electrode / dye is absorbed. More specifically, the lower substrate, the cathode, the titanium oxide layer that has absorbed the dye, the electrolyte layer, the anode, and the upper substrate are successively laminated from the lower layer. At this point, the upper and lower substrates are typically prepared from glass or plastic, the cathode is coated with ITO (indium tin oxide) or FTO (fluorine-doped tin oxide), and the anode is coated with platinum. .

  In view of the principle of operation of the conventional dye-sensitized solar cell element configured as described above, the dye absorbs photons and forms excitons (electron-hole pairs). The excitons transition from the ground state to the excited state when the titanium oxide layer that has absorbed the dye is irradiated with light. Thus, electron-hole pairs are separated from each other, electrons are injected into the titanium oxide layer, and holes are transferred to the electrolyte layer. When the external circuit is set up according to the above, electrons move from the cathode through the conductive line to the anode through the titanium oxide layer to generate a current. The electrons in the anode are reduced by the electrolyte and the excited electrons continue to be transferred to the generated current.

  However, while a general dye-sensitized solar cell element has high energy conversion efficiency, it has safety problems such as property deterioration due to evaporation of a solution, leakage of an electrolyte, and the like. Such problems constitute a major barrier to commercialization. Various studies have been conducted to avoid such electrolyte leakage. In particular, in order to increase the stability and durability of solar cells, dye-sensitized solar cells using semi-solid or solid electrolytes have been developed.

  For example, Korean Patent Application Publication No. KR2003-65957 discloses a dye-sensitized solar cell containing polyvinylidene fluoride dissolved in a solvent such as N-methyl-2-pyrrolidone or 3-methoxypropionitrile. . The gel type polymer electrolyte prepared by such a method has high ionic conductivity at room temperature like the liquid electrolyte, but has inferior mechanical properties and low liquid retention of the polymer electrolyte. Make the manufacturing process difficult.

  There has been active research using electrospinning as a technique for producing such polymer electrolyte membranes. Electrospinning was filed as a patent application in 1934 by Formhals (German engineer). The scientific foundation of electrospinning was developed from the 1882 Raleigh concept that electrostatic forces can overcome the surface tension of the liquid as it falls. Polymer fibers produced by electrospinning have been incorporated into ultra-fine nanotechnology, with a global market scale of approximately $ 1 trillion in 2100. In general, nanofibers are defined as fibers produced by electrospinning that have a diameter of 20 nm to 1 μm, spin the polymer as fibers in a low viscosity state, and then separate with electrostatic forces. Since mass production is possible, there are applications such as nanoparticles and filters, fuel cell electrolytes, and medical applications. Its use is expected to continue to grow.

  The greatest advantage of nanofibers is that they have a larger surface area compared to conventional fibers. Such advantages allow nanofibers to be used as an efficient material for the filter. Nanofibers by electrospinning can also be used in protective clothing, antibiotic wound dressings, drug delivery materials and the like. However, such nanofibers can only be produced by electrospinning, and the fibers are formed irregularly. Therefore, it is difficult to control fiber formation. In order to solve such a problem, there has been considered a method of collecting an electric field on one side by sharpening an end of a rotating focus plate. Another method of arranging the nanofibers in a certain direction during the process is also conceivable by using a gap focus plate. The mutual gap is formed by the electric field in the vicinity of the focus plate and the electrostatic charge of the fibers. Thus, the produced fiber is prepared. Recently, nanofibers have been regarded as biomedical implantable materials because of their high porosity and large surface area. Thus, such features can be useful for cell adhesion, growth, proliferation, and the like. However, nanofibers produced by electrospinning have poor physical properties because little improvement in strength is obtained due to the molecular arrangement of the polymer itself. In order to eliminate such problems, various process parameters are used in many studies aimed at nanofiber preparation.

  Akron University's Reneker has announced how to adjust the influencing factors of nanofiber production and electrospinning methods for various polymer materials. In addition, Drexel University has produced nanocomposites with improved mechanical properties by supplementing carbon nanotubes with electrospinning. Deitzel announced that as the polymer concentration increases, the nanofiber diameter and fiber diameter tend to increase by increasing the polymer concentration according to the power law relationship. Doshi and Reneker announced that the lower the surface tension of the polymer solution, the lower the bead in the fiber.

  Research has continued on electrospinning processes and product development for biological applications and polymeric materials. Commonwealth University has succeeded in producing a nanosized fine cellulose originally present in blood to produce a flannel-shaped bandage by using electrospinning technology. Ethicon Inc. manufactured a PDO monofilament suture (PDS) using p-dioxanone as a raw material. Woodward et al. (1985) suggested that heat treatment was necessary because the degree of crystallinity of non-woven fabrics produced by electrospinning was much lower than the crystallinity of the polymer before electrospinning. Ignatius has demonstrated that drugs can be administered immediately at any time by using electrospun nanofibers. The MIT Material Processing Center conducted research on substrates for artificial organs, and the University of Harvard conducted research on nanofibers using non-tissues. MIT ISN (Institute for Soldier Nanotechnologies) Rutledge has a size of 0.5 μm to 10 μm and uses PCL nanofibers that have been electrospun. And developed nanofibers to treat damaged articular cartilage. Israel's Yarin (2004) suggests a new method in which the polymer solution is placed at the bottom and then subjected to upward spinning by using a ferromagnetic suspension system instead of the traditional spinning method did.

  Research aimed at producing nanofibers using electrospinning has been conducted at various universities and research institutions in the country. However, these studies largely depended on experiments, and the subject of the study was the characteristics and morphology of the nanofibers that were probed in the experiments when the process parameters were changed.

  In the case of solar cells using a solid electrolyte, the solvent is removed from the electrolyte solution to compensate for the efficiency loss due to the solvent. Next, electrons entering through the cathode electrode are easily reduced by using a solid-state hole conducting material that conducts current as the dye is oxidized.

Research on solar cells using solid polymer electrolytes without solvents was first attempted in 2001 by the De Paoli group in Brazil. This group was reported to produce a polymer electrolyte comprising poly (epichlorohydrin-co-ethylene oxide) / NaI / I ₂ and have an energy conversion efficiency of about 1.6% at 100 mW / cm ² . . Later, the Flaras group improved the mobility of I ⁻ / I ₃ ⁻ in 2002 by adding titanium oxide nanoparticles to highly crystalline polyethylene oxide to reduce the crystallinity of the polymer. I did research. KIST's Center for Facilitated Transport Membrane of KIST conducted research to efficiently add low molecular weight polyethylene glycol (PEG) to dye-sensitized solar cells using hydrogen bonding in 2004. The resulting energy conversion efficiency was reported to be about 3.5%.

Recently, the Flavia Nogueira group introduced ethylene oxide and epichlorohydrin as a polymer electrolyte in a ratio of 84:16 by using poly (ethylene oxide-co-epichlorohydrin) in 2007. A solid dye-sensitized solar cell in the form of a synthesized TiO ₂ nanotube was manufactured and reported an energy conversion efficiency of 4.03%.

There remains a strong need in the art to develop solid dye-sensitized solar cell elements that overcome the above problems without reducing ionic conductivity and without compromising solid morphology.
The present invention is configured to eliminate the above-described conventional problems. As one object of the present invention, electrospun nanoscale polymer fibers are added to the electrolyte of the polymer thin film electrolyte to produce a high performance dye-sensitized solar cell.

Another object of the present invention is produced by efficiently inducing an increase in photocurrent in a dye-sensitized solar cell using polymer nanofibers having a high specific surface area in producing an electrolyte layer. It is to provide a high-performance dye-sensitized solar cell. The invention also relates to a method for producing the above.
Still another object of the present invention is to provide a dye-sensitized solar cell having an increased photocurrent by introducing a functional layer that prevents reverse current from the inorganic oxide layer, and a method for producing the dye-sensitized solar cell. Is to provide.
Still another object of the present invention is to provide a dye-sensitized solar cell having an increased photocurrent by introducing a light scattering layer on the inorganic layer so that light passing through the inorganic oxide layer is subjected to a light scattering effect. Is to provide. As a result, a large amount of light can be absorbed. The invention also relates to means for providing the above.

In order to achieve the above object, the present invention provides:
A first substrate and a second substrate arranged to face each other;
A first electrode disposed between a first substrate and a second substrate, the dye layer being chemically absorbed into the inorganic oxide layer and the inorganic oxide layer to provide excitation electrons A first electrode comprising:
A second electrode disposed opposite to the first electrode, the second electrode disposed between the first substrate and the second substrate, thereby allowing a current to flow; ,
A first interfacial bonding layer that facilitates interfacial bonding of the inorganic oxide layer onto the inorganic oxide layer;
A second interface bonding layer that avoids reverse current on the first interface bonding layer;
A light scattering layer disposed between the first interface bonding layer and the second interface bonding layer, the light scattering layer increasing light absorption;
A solid electrolyte disposed between a first electrode and a second electrode, comprising polymer nanofibers produced by an electrospinning method and capable of providing electrons to the dye layer by a redox reaction; Provided is a dye-sensitized solar cell comprising a solid electrolyte.

To achieve the above object, the present invention provides a method for producing a dye-sensitized solar cell,
Preparing a first substrate;
Forming an inorganic oxide layer on one surface of the first substrate to form a first electrode;
Forming a first interface bonding layer that facilitates interfacial bonding of the inorganic oxide layer onto the inorganic oxide layer;
Forming a light scattering layer on the first interfacial bonding layer to increase absorption;
Forming a second interface bonding layer on the light scattering layer to avoid reverse current;
Absorbing a dye layer on the second interfacial bonding layer;
The electrospinning apparatus is used to electrospin the polymer solution onto the second interfacial bonding layer in which the dye layer is absorbed, the electrolyte solution is applied to the polymer nanofibers, and then the applied solution is evaporated. Forming a solid electrolyte, and forming a second electrode and a second substrate on the solid electrolyte.

When conventional liquid and semi-solid electrolytes are used in dye-sensitized solar cells, there are leakage problems, long-term stability problems, and problems caused by contact between the electrode and the counter electrode due to electrolyte evaporation.
The present invention is configured to eliminate such problems by introducing polymer nanofibers into the electrolyte layer. As shown in the examples, dye-sensitized solar cells are prepared by using principles that can overcome the above problems by preparing polymer nanofibers under various conditions.
The reverse current appears mainly at the interface between the inorganic oxide layer and the electrolyte layer, and the reverse current can be avoided by introducing an interface bonding layer. The amount of photocurrent is increased by introducing a light scattering layer to facilitate light reabsorption. Further, the advantages obtained by introducing nanoscale polymer fibers into the electrolyte layer are as follows.

First, the polymer nanofibers have a high specific surface and a plurality of pores, which can efficiently contain and implant electrolyte ions. Therefore, better short circuit current and photovoltaic efficiency can be provided compared to polymer thin films prepared by spin coating.
Secondly, the polymer nanofibers avoid a short circuit due to contact between the working electrode and the counter electrode due to leakage of the liquid electrolyte in the dye-sensitized solar cell using the liquid electrolyte. Therefore, the problem of long-term stability in the conventional liquid or semi-solid dye-sensitized solar cell can be solved. Therefore, durability can be maintained.
Third, a reverse current is avoided by the functional layer and the light scattering layer introduced on the inorganic oxide layer. The transmitted light can be reabsorbed in the light scattering layer to increase the photocurrent. Therefore, the overall efficiency of the dye-sensitized solar cell can be improved.
Finally, electrospun polymer nanofibers have superior photovoltaic efficiency compared to conventional polymer films. This indicates the possibility of developing solid-type dye-sensitized solar cells.

It is sectional drawing of the structure of the dye-sensitized solar cell element prepared by this invention. It is sectional drawing of the structure of the electrospinning apparatus used in this invention. It is a SEM image of the surface after the inorganic oxide layer was prepared by the Example of this invention. It is a SEM image of the surface after a light-scattering layer was prepared on the inorganic oxide layer prepared by the Example of this invention. It is a SEM image of the side view after the light-scattering layer was prepared on the inorganic oxide layer prepared by the Example of this invention. FIG. 2 is an SEM image of a surface of PVDF-HFP and an image of a distribution of diameters, respectively, having a nano-sized diameter and prepared according to an embodiment of the present invention. FIG. 5 is an SEM image of the surface after fibers have been prepared by adding Ag in proportion to their respective mass percentages relative to PVDF-HFP having nanoscale diameters and prepared according to examples of the present invention. Surface after fibers have been prepared by adding inorganic nanofiller Al ₂ O ₃ in proportion to the respective mass percent of PVDF-HFP having a nanoscale diameter and prepared according to embodiments of the present invention It is a SEM image of. SEM of the surface after the fibers have been prepared by adding inorganic nanofiller BaTiO ₃ in proportion to the respective mass percent of PVDF-HFP having a nanoscale diameter and prepared according to an embodiment of the present invention It is an image. FIG. 2 is an SEM image and a diameter distribution image, respectively, of the surface of a PVA fiber having a nanoscale diameter and prepared according to an embodiment of the present invention. 2 is an SEM image of the surface of a PVA fiber containing silver, having a nanoscale diameter, prepared according to an example of the present invention. 2 is a SEM image of the surface of a PVDF and PS blend fiber having a nanoscale diameter and prepared according to an example of the present invention. 2 is a SEM image of the surface of a PVDF and PMMA mixed fiber having a nanoscale diameter and prepared according to an example of the present invention. FIG. 6 is a graph of voltage-current density at 100 mW / cm ² illumination of a dye-sensitized solar cell element using PVDF-HFP fibers having a nano-scale diameter and prepared according to an example of the present invention. 6 is a graph of voltage-current density under dark conditions of a dye-sensitized solar cell element using PVDF-HFP fiber having a nano-scale diameter and prepared according to an example of the present invention. 100 mW / cm ² illumination of a dye-sensitized solar cell element using a fiber comprising an inorganic nanofiller Al ₂ O ₃ and a PVDF-HFP fiber having a nanoscale diameter and prepared according to an embodiment of the present invention It is a graph of the voltage-current density in FIG. 100 mW / cm ² illumination of a dye-sensitized solar cell element using a fiber comprising an inorganic nanofiller BaTiO ₃ and a PVDF-HFP fiber having a nanoscale diameter and prepared according to an embodiment of the present invention It is a graph of voltage-current density. FIG. 4 is a graph of voltage-current density at 100 mW / cm ² illumination of a dye-sensitized solar cell element using PVA fibers having a nanoscale diameter and prepared according to an embodiment of the present invention. FIG. 6 is a graph of voltage-current density in the dark condition of a dye-sensitized solar cell element using a PVA fiber having a nano-scale diameter and prepared according to an embodiment of the present invention. FIG. 4 is a graph of voltage-current density at 100 mW / cm ² illumination of a dye-sensitized solar cell element using a PVA fiber having a nanoscale diameter and prepared according to an example of the present invention and containing Ag. Impedance of a dye-sensitized solar cell element using a PVDF-HFP fiber having a nano-scale diameter and prepared according to an embodiment of the present invention and a dye-sensitized solar cell element including a light scattering layer and an interface bonding layer A comparison of Bode diagrams is shown. Bode lines of impedance between dye-sensitized solar cell elements using PVDF-HFP fibers and dye-sensitized solar cell elements using PVDF-HFP thin films having nanoscale diameters and prepared according to embodiments of the present invention A comparison of the figures is shown. Dye-sensitized solar cell element using a PVDF-HFP fiber having a nano-scale diameter and prepared according to an embodiment of the present invention and a dye-sensitized solar cell element using PVDF-HFP manufactured by a spin coating method A comparison of the Nyquist diagram of impedance is shown. Impedance between a dye-sensitized solar cell element using a PVA fiber having a nano-scale diameter and prepared according to an embodiment of the present invention and a dye-sensitized solar cell element using a PVA thin film manufactured by a spin coating method Comparison of Bode plots is shown. Impedance between a dye-sensitized solar cell element using a PVA fiber having a nano-scale diameter and prepared according to an embodiment of the present invention and a dye-sensitized solar cell element using a PVA thin film manufactured by a spin coating method Comparison of Nyquist diagrams is shown. Impedance Bode lines between dye-sensitized solar cell elements using PVA fibers having a nanoscale diameter and prepared according to embodiments of the present invention and dye-sensitized solar cell elements using PVA thin films containing silver A comparison of the figures is shown. Nyquist line of impedance between a dye-sensitized solar cell element using a PVA fiber having a nano-scale diameter and prepared according to an embodiment of the present invention and a dye-sensitized solar cell element using a PVA thin film containing silver A comparison of the figures is shown. Have a diameter of nanoscale, prepared by Examples of the present invention, it shows a comparison of Bode plot of the impedance of the dye-sensitized solar cell element using the PVDF fibers containing an organic nanofiller Al ₂ O _3. Have a diameter of nanoscale, prepared by Examples of the present invention, it shows a comparison of the Nyquist diagram of the impedance of the dye-sensitized solar cell element using the PVDF fibers containing an organic nanofiller Al ₂ O _3. FIG. 30 is an image of an electrolyte durability test using PVDF-HFP fibers having a nano-scale diameter and prepared according to an embodiment of the present invention, where A in FIG. 30 is bonded to a glass substrate, and then the electrolyte 30 is an image after 0 hour from the introduction of A, and A-1 in FIG. 30 is an image after 0 hour after the fiber is introduced, the glass substrate is joined, and then the electrolyte is introduced. B in FIG. 30 is an image 12 hours after the glass substrate is joined and then only the electrolyte is introduced, and B-1 in FIG. 30 is a fiber introduced and the glass substrate is joined. Next, an image 12 hours after the introduction of the electrolyte, C in FIG. 30 is an image 36 hours after the glass substrate is bonded and then only the electrolyte is introduced, C-1 in FIG. 30 indicates that fibers are introduced and the glass substrate is bonded. Next, it is an image 36 hours after the introduction of the electrolyte, and D in FIG. 30 is an image 48 hours after the glass substrate is bonded and then only the electrolyte is introduced. D-1 in 30 is an image 48 hours after the fiber is introduced, the glass substrate is bonded, and then the electrolyte is introduced. E in FIG. 30 is D-1 in FIG. It is an image in which the fibers are held after the glass substrate is removed. 6 is a voltage-current density graph of a dye-sensitized solar cell element using a spin-coated PVDF-HFP thin film according to Comparative Example 1. 6 is a graph of voltage-current density of a dye-sensitized solar cell element using a spin-coated PVA thin film according to Comparative Example 2. It is a graph of the voltage-current density of the dye-sensitized solar cell element prepared by adding only an electrolyte without a fiber by the comparative example 3.

  Common liquid dye-sensitized solar cell elements having an electrolyte that contains a solvent rather than a polymer have problems with electrolyte leakage and long-term stability. Contact between the first electrode and the second electrode due to electrolyte leakage also reduces the lifetime of the device. Furthermore, in the case of a solid dye-sensitized solar cell element incorporating a polymer electrolyte, the polymer is in a randomly mixed state. Accordingly, the inventors of the present invention have developed a dye-sensitized solar cell that can solve the above problems by producing polymer nanofibers by electrospinning the polymer and then incorporating the nanofibers into the electrolyte. A device was prepared.

  The present invention provides an electrolyte thin film for a dye-sensitized solar cell comprising nanofibers made by electrospinning a specific chemical.

  FIG. 1 is a cross-sectional view of a dye-sensitized solar cell element prepared according to a preferred embodiment of the present invention by utilizing an electrolyte incorporating electrospun nanofibers. As shown in FIG. 1, the dye-sensitized solar cell element prepared according to the preferred embodiment of the present invention is in the form of a multilayer thin film, and is first opposed to each other and disposed between two transparent substrates. Electrode (1002) and second electrode (1009), first substrate (1001) and second substrate (1010), inorganic oxide layer (1003), interface bonding layers I and II (1004 and 1006), a scattering layer (1005), a dye layer (1007), and a polymer electrolyte layer (1008) disposed between the first electrode (1002) and the second electrode (1009).

The first substrate (1001) is made of, for example, glass or plastic containing PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene), PI (polyamide), TAC (cellulose triacetate), or the like. Can be made of transparent material. The first substrate (1001) is preferably made of glass.
The first electrode (1002) is an electrode formed on one side of the first substrate (1001) with a transparent material. The first electrode (1002) functions as a cathode. For the first electrode (1002), any material having a work function, transparency, and conductivity lower than those of the second electrode (1005) can be used. In the present invention, the first electrode (1002) can be applied or thinly coated on the back surface of the first substrate (1001) by using a sputtering method or a spin coating method.

Examples of materials that can be used as the first electrode (1002) include ITO (indium tin oxide), FTO (fluorine-doped tin oxide), ZnO— (Ga ₂ O ₃ or Al ₂ O ₃ ), SnO ₂ —. Any of Sb ₂ O _{3 and the} like is included. More preferably, ITO or FTO is used.

The inorganic oxide layer (1003) is preferably a transition metal oxide in the form of nanoparticles, such as titanium oxide, scandium oxide, vanadium oxide, zinc oxide, gallium oxide, yttrium oxide, zirconium oxide, niobium oxide, molybdenum oxide. Transition metal oxides such as indium oxide, tin oxide, lanthanum group oxide, tungsten oxide, and iridium oxide; alkaline earth metal oxides such as magnesium oxide and strontium oxide; and aluminum oxide. In particular, titanium oxide in the form of nanoparticles is most preferred.
The inorganic oxide layer (1003) is applied to the first electrode (1002) by a coating process on one surface of the first electrode (1002) following the heat treatment. Generally, a doctor blade method or a screen printing method is used to coat a paste containing an inorganic oxide on the back surface of the first electrode (1002) with a thickness of about 5 μm to 30 μm, preferably 10 μm to 15 μm. The Spin coating, spraying, and liquid coating methods may be used.

  A functional layer having several functions can be introduced on the inorganic oxide layer (1003) constituting the dye-sensitized solar cell element according to the present invention before absorbing the dye. Prior to the introduction of the light scattering layer (1005), a first interface bonding layer (1004) intended to facilitate interface bonding can be formed on the inorganic oxide layer (1003).

  The surface of the first interfacial bonding layer (1004) should preferably have an evenly distributed nanoparticle and smoothness and a more complex structure than the inorganic oxide layer (1003). The interface bonding layer I can be formed by any known method conventionally used in the art. However, generally, a paste containing an inorganic oxide is applied to the inorganic oxide layer (1003) by spin coating or dipping in a thickness of about 2 nm to 100 nm, preferably about 10 nm to 100 nm, more preferably 30 nm to 50 nm. Used to coat the back side of Alternatively, heat treatment is performed after using a spin coating method, a spray method, or a liquid coating method. These layers generally comprise at least an inorganic oxide, preferably a transition metal oxide, alkali metal oxide, or alkaline earth metal oxide, more preferably a semiconductor oxide. The constituent elements of the interface bonding layer I may be the same as or different from the constituent elements of the inorganic oxide layer (1003). The interface bonding layer I includes, for example, titanium oxide, scandium oxide, vanadium oxide, zinc oxide, gallium oxide, yttrium oxide, zirconium oxide, niobium oxide, molybdenum oxide, indium oxide, tin oxide, lanthanum group oxide, tungsten oxide, and Transition metal oxides such as iridium oxide; alkaline earth metal oxides such as calcium oxide, magnesium oxide, and strontium oxide; aluminum oxide, sodium oxide, cerium oxide, nickel oxide, sodium titanate, potassium niobate, barium titanate , Strontium titanate, and a mixture of at least two of said oxides. In a specific embodiment, the interface bonding layer I is formed of any one component of the inorganic oxide layer (1003) or the compound containing the inorganic oxide layer (1003) as a component. For example, the interface bonding layer I may be formed of at least one of titanium oxide, tungsten oxide, and an oxide of a titanium-tungsten mixture. More preferably, titanium oxide is used. The reason is that titanium oxide has the most favorable HOMO (highest occupied molecular orbital) value and LUMO (lowest unoccupied molecular orbital) value for electron transfer.

  In a preferred embodiment, the interfacial bonding layer I is formed from an inorganic oxide in the form of nanoparticles, and the particles have an average diameter of 1 nm to 50 nm, preferably 2 nm to 30 nm, more preferably 5 nm to 20 nm. When the average diameter of the particles is less than 1 nm, an agglomeration phenomenon occurs between the particles, and therefore it is difficult to prepare a thin film having a uniform thickness. Rather, an increase in resistance in the interface bonding layer leads to a reduction in fill factor (FF). Conversely, when the average diameter of the particles is greater than 50 nm, the thickness and porosity of the interfacial bonding layer increases, and thus the amount of electrons lost during electron transfer, thereby increasing the photocurrent value and FF. It leads to reduction. In the present invention, the average particle diameter refers to the average value of the diameters of 500 particles measured through scanning of a microscope image.

  On the introduced first interface bonding layer (1004), a light scattering layer (1005) serving to increase the amount of light absorption is introduced. These layers generally contain at least an inorganic oxide, preferably a transition metal oxide, an alkali metal oxide, or an alkaline earth metal oxide, and more preferably a semiconductor oxide. The components of the light scattering layer may be the same as or different from the components of the inorganic oxide layer (1003) or the interface bonding layer. The light scattering layer is, for example, titanium oxide, scandium oxide, vanadium oxide, zinc oxide, gallium oxide, yttrium oxide, zirconium oxide, niobium oxide, molybdenum oxide, indium oxide, tin oxide, lanthanum oxide, tungsten oxide, and oxide. Transition metal oxides such as iridium; alkaline earth metal oxides such as calcium oxide, magnesium oxide, strontium oxide; aluminum oxide, sodium oxide, cerium oxide, nickel oxide, sodium titanate, potassium niobate, barium titanate, titanium Strontium acid, as well as a mixture of at least two of said oxides. In a specific embodiment, the light scattering layer is formed of any one component of the inorganic oxide layer (1003) or the compound containing the inorganic oxide layer (1003) as a component. For example, the light scattering layer may be formed of at least one of titanium oxide, tungsten oxide, and an oxide of a titanium-tungsten mixture. More preferably, titanium oxide is used. This is because titanium oxide has the most favorable HOMO and LUMO values for electron transfer.

  In a preferred embodiment, the light scattering layer is formed from an inorganic oxide in the form of fine particles, and the particles have an average diameter of 20 nm to 1 μm, preferably 50 nm to 600 nm, more preferably 100 nm to 500 nm. If the average diameter of the particles is less than 20 nm, most of the light is transmitted and the desired light scattering effect cannot be obtained. Conversely, if the average diameter of the particles is greater than 1 μm, the layer thickness and porosity increase, which in turn increases the amount of electrons lost during electron transfer, thereby reducing the photocurrent value and FF. As a result, the efficiency is lowered. Furthermore, increasing the particle size of the inorganic oxide reduces the permeability. Therefore, the dye-sensitized solar cell element thus prepared becomes opaque and its use is limited. The light scattering layer can be formed by any known method conventionally used in the art. However, generally, a doctor blade method or a screen printing method is used, and a paste containing an inorganic oxide is coated on the back surface of the inorganic oxide layer (1003) to which the first interface bonding layer (1004) is applied. The thickness is about 500 nm to 50 μm, preferably about 1 μm to 30 μm, more preferably 3 μm to 25 μm, and most preferably 5 μm to 20 μm. Alternatively, heat treatment is performed after using a spin coating method, a spray method, a dipping method, or a liquid coating method.

  A second interface bonding layer (1006) for avoiding a reverse current is introduced on the light scattering layer (1005). The second interface bonding layer can be formed in the same manner as the first interface bonding layer (1004). In a preferred embodiment, the two interfacial bonding layers share the same components, particle size, etc. In many cases, the reverse current is generated in the course of electron transfer in the dye-sensitized solar cell. First, when electrons transported from the dye layer to the inorganic oxide layer fail to transport to the transparent electrode and are sent back to the electrolyte layer, thereby reducing the amount of electrons collected on the transparent electrode. Can occur. This is mainly due to the direct contact between the inorganic oxide layer and the electrolyte layer at the incompletely coated portion of the inorganic oxide layer. This direct contact is achieved by using the interface layer or the like for the inorganic oxide layer. It can be avoided by protecting. Further, the reverse current can occur when electrons collected on the transparent electrode through the inorganic oxide layer flow back to the electrolyte layer, thereby reducing the value of the photocurrent. This occurs in the pores generated during the application of the inorganic oxide layer, and this pore formation occurs before the inorganic oxide layer is applied to the transparent electrode. This can be avoided by applying

  Therefore, when irradiated with sunlight, photons are absorbed into the dye layer (1007) absorbed by the inorganic oxide layer into which the light scattering layer and the functional layer are introduced, and the dye is brought into an excited state to make an electronic transition. Thereby forming an electron-hole pair. The excited electrons are injected into the conduction band in the inorganic oxide layer, and the injected electrons are transported to the first electrode (1002) and then transported to the second electrode (1009) via an external circuit. Is done. The transported electrons are transported to the electrolyte layer (1008) by oxidation / reduction by an electrolyte component included in the electrolyte layer (1008).

  On the other hand, after the electrons are transported into the inorganic oxide, the dye is oxidized, but is reduced by the electrons transported from the electrolyte layer (1008). Therefore, the electrolyte layer (1008) functions as transporting electrons from the second electrode (1009) to the dye.

The photosensitive dye chemically absorbed in the inorganic oxide layer (1003) according to the present invention includes a dye such as a ruthenium compound as a material capable of absorbing ultraviolet light and light in the visible light region. The photosensitive dye absorbed in the inorganic oxide layer (1003) includes a ruthenium complex such as a ruthenium 535 dye, a ruthenium 535 bis-TBA dye, and a ruthenium 620-1H3TBA dye. Preferably, ruthenium 535 dye is used. Further, the photosensitive dye chemically absorbed in the inorganic oxide layer (1003) can be any dye capable of separating charges, and besides a ruthenium dye, a xanthan dye, a cyanine dye, a porphyrin System dyes and anthraquinone dyes.
Conventional methods may be used to absorb the dye into the inorganic oxide layer (1003). However, the dye is dissolved in a solvent such as alcohol, nitrile, halogenated hydrocarbon, ether, amide, ester, ketone, N-methylpyrrolidone, and then the photoelectrode coated with the inorganic oxide layer (1003) is used as a solution. The method of impregnating in is preferable.

On the other hand, the electrolyte layer (1008) uses an electrolyte in which an electrolyte composition contained in an electrolyte layer of a conventional solar cell element is mixed with the electrospun polymer nanofiber of the present invention. PVDF, PVDF-HFP, PAN, PEO, PMMA, PVA and the like are preferable for use in electrospinning, and PVDF-HFP is more preferable.
Polymer nanofibers prepared via the electrospinning method have a ratio of 5:95 weight percent, preferably 20:80 weight percent, more preferably 40:60 weight percent, based on the total amount of electrolyte layer (1008). Mixed in.

  FIG. 2 shows a schematic view of an electrospinning apparatus. The electrospinning apparatus includes a voltage supply source (2001) for applying a voltage to form nanofibers, a solution transporter (2002) for periodically spraying a polymer solution, and a voltage applied from the voltage supply source. Using an electrospinner (2003) for producing polymer nanofibers from a polymer solution transported from a solution transporter, and a collector (2004) for collecting nanofibers spun from the electrospinner.

  The nanofiber added in the electrolyte layer (1008) will be described in detail. First, when the polymer nanofibers are prepared by polymer concentration by electrospinning, the polymer used is mixed with the solvent in an amount of 5 to 19 weight percent, preferably 11 to 17 weight percent. As a solvent used herein, for example, dimethylacetamide and acetone may be present in a mass ratio of 3: 7.

Meanwhile, the solid electrolyte of the present invention may further include a nano-sized metal additive (for example, Ag) or an inorganic nano filler. As the inorganic nanofiller, Al ₂ O ₃ or BaTiO ₃ is preferable, but not limited thereto.
When the metal additive is introduced into the polymer nanofiber, the metal additive is present in an amount of 0.1 to 30 weight percent, preferably 1 to 20 weight percent, based on the polymer concentration of the solution used for electrospinning. Can be mixed with solvent. When the inorganic nanofiller additive is introduced into the polymer nanofiber, the inorganic nanofiller additive is 1 to 50 weight percent, preferably 10 to 40 weight percent based on the polymer concentration of the solution used for electrospinning. Can be mixed with the solvent in the amount of.

  Second, when the polymer nanofibers are prepared with an applied voltage by an electrospinning method, the electrospinning is maintained at a polymer mass and spinning distance (TCD) of 15 weight percent and 15 cm, respectively, It is performed under the condition that the range of the applied voltage is 6 kV to 25 kV, preferably 8 kV to 20 kV.

Finally, when polymer nanofibers are prepared by TCD by electrospinning method, electrospinning is fixed at polymer mass and applied voltage of 15 mass percent and 14 kV, respectively, and TCD is 9 cm to 21 cm, preferably 13 cm to 19 cm. It is executed under the condition that In the solution transporter, the polymer solution is supplied at a flow rate of 1 ml / h to 5 ml / h, preferably 2 ml / h.
When polymer nanofibers are prepared by the electrospinning method described above, the polymer concentration range is 11-17 mass percent, the applied voltage is 8 kV-14 kV, the TCD is 13 cm-19 cm, and the solution is 2 ml / h. Most preferably, the conditions are as follows:

Further, the electrolyte used for the electrolyte layer (1008) can include a combination of I ₂ and a metal iodide or an organic iodide (metal iodide or organic iodide / I ₂ ) as a redox pair. Further, a combination of Br ₂ and a metal bromide or organic bromide (metal bromide or organic bromide / Br ₂ ) may be used as a redox pair.
In the electrolyte used in the present invention, the metal cation in the metal iodide or metal bromide includes Li, Na, K, Mg, Ca, Cs and the like. As the cation in the organic iodide or the organic bromide, ammonia compounds such as imidazolium, tetraalkylammonium, pyridinium, triazolium are suitable, but the cation is not limited to the compounds listed above. For use in the electrolyte may be a mixture of at least two compounds selected from the redox pair combination of LiI or imidazolium iodide and I ₂ is particularly preferable.

When the above-mentioned solvent is used in the electrolyte composition according to the present invention, metal iodide or metal bromide is combined with iodide (I ₂ ) or bromide (Br ₂ ), and the combined product is used as a redox pair. be able to. Therefore, the redox couples LiI / I ₂ , KI / I ₂ , NaI / I ₂ , CsI / I ₂ , Pr ₄ NI (tetrapropylammonium iodide) / I ₂ , TBAI (tetrabutylammonium iodide) / I ₂ Etc., preferably a TBAI / I ₂ pair is used.

Among the electrolytes usable according to the present invention, n-methylimidazolium iodide, 1-benzyl-2-methylimidazolium iodide, 1-ethyl-3-methylimidazolium can be used as an organic halide usable as an ionic liquid. Examples include iodide, 1-butyl-3-methylimidazolium iodide, and the like. In particular, 1-ethyl-3-methylimidazolium iodide is preferred, and the materials listed above may be used in combination with iodide (I ₂ ). When an ionic liquid, that is, a dissolved salt or the like is used, the electrolyte composition can form a solid electrolyte in the absence of a solvent.

On the other hand, the second electrode (1009) coated on the opposite surface of the second substrate (1010) functions as an anode. The second electrode (1009) can be sprayed or coated on the opposite surface of the second substrate (1010) by using sputtering or spin coating.
The material that can be used for the second electrode (1009) is a material having a work function larger than that of the material used for the first electrode (1002), and includes platinum (Pt), gold, carbon, and the like. Is preferred.
The second substrate (1010) is a transparent material similar to the first substrate (1001). The second substrate (1010) is made of a transparent material such as glass or plastic including PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene), PI (polyamide), TAC (cellulose triacetate). Can be prepared, preferably from glass.

The dye-sensitized solar cell prepared according to the preferred embodiment of the present invention is manufactured as follows.
First, an inorganic oxide, preferably colloidal titanium oxide, is sprayed or coated on the surface of the first substrate coated with the first electrode material at a thickness of about 5 nm to 30 μm, and about 450 ° C. to about Sintering is performed at a temperature of 550 ° C. to form a first substrate / first electrode / inorganic oxide film / laminated photoelectrode from which organic substances are removed. Subsequently, in order to make the prepared inorganic oxide layer absorb the dye, a dye, for example, ruthenium 535, is added to the ethanol solution prepared in advance to prepare the dye solution. Thereafter, a transparent substrate coated with an inorganic oxide layer (for example, a photoelectrode or glass substrate coated with FTO) is placed in the formed dye solution, whereby the dye is absorbed into the inorganic oxide layer. The After the dye was completely absorbed by the inorganic oxide layer, the inorganic oxide layer was washed with ethanol or the like and dried in order to remove the physically absorbed dye.
When a transparent substrate coated with an inorganic oxide layer that has absorbed a dye is prepared, the polymer fiber according to the present invention is prepared by adding an electrolyte solution to be used as an electrolyte and sintering a platinum precursor. A platinum electrode is joined to a glass substrate to obtain a dye-sensitized solar cell according to the present invention.

Example 1 Preparation of Inorganic Oxide Layer Introduced with Interfacial Bonding Layer (BL) and Scattering Layer (SL) Spin coating method using a mixed solution of titanium (IV) isopropoxide and ethanol at a volume ratio of 1:10 Then, the mixed solution was thinly applied at 1500 rpm for 20 seconds on an FTO glass substrate (fluorine-doped tin oxide, SnO ₂ : F, 15Ω / sq) cut to a size of 15 mm × 15 mm. This was then placed in an electric crucible, the temperature was raised from room temperature to 500 ° C., the organic compound was removed for about 30 minutes and allowed to cool to room temperature. The heating rate and cooling rate are each about 5 ° C./min. A colloidal titanium oxide paste having a particle size of 9 nm is thinly applied to a substrate so as to have a thickness of about 10 μm by the doctor blade method, and then placed in an electric crucible, and the temperature is raised from room temperature to 500 ° C. Until cooled. Next, by introducing the interface bonding layer I in the same manner as the first method, a mixed solution of titanium (IV) isopropoxide and ethanol is thinly applied to the substrate, and then placed in an electric crucible, and the temperature is set. The temperature was raised from room temperature to 500 ° C. and cooled to room temperature. After colloidal titanium oxide paste having a particle size of 300 nm was thinly applied to the substrate by the doctor blade method, the temperature was raised from room temperature to 500 ° C. and cooled to room temperature. The absorption of light is increased by introducing a TiO ₂ layer having a particle size of 300 nm or more and scattering the light. Finally, after a thin solution of a mixed solution of titanium (IV) isopropoxide and ethanol is applied to the substrate, it is placed in an electric crucible, the temperature is raised from room temperature to 500 ° C., and cooled to room temperature. The interface bonding layer II was introduced in the same manner as described above. 3 to 5 show an SEM diagram and a side cross-sectional view of an inorganic oxide layer having an introduced interface bonding layer and a light scattering layer on the inorganic oxide layer.

Example 2: Absorption of dye A substrate on which organic compounds have been removed and only titanium oxide has been applied is placed in a dye solution for 24 hours at room temperature to allow the titanium oxide layer to absorb the dye. The dye used is cis-bis (isothiocyanato) bis (2,2′-bipyridyl-4,4′-dicarboxylate) -ruthenium (II) (ruthenium 535) commercially available from Solaronix (Switzerland). Dye). A solution of ruthenium 535 dye was prepared by dissolving ruthenium 535 dye in 100 ml ethanol at a concentration of 20 mg. After immersing the titanium oxide substrate for 24 hours and removing it from the solution, the titanium oxide substrate that has absorbed the dye is washed again with ethanol to remove the physically absorbed dye layer, and then the substrate is again at 60 ° C. Dried.

  Dye 2 was used in a dye-sensitized solar cell using polyvinyl alcohol fiber. The dye used was cis-diisothiocyanato-bis (2,2-bipyridyl-4,4-dicarboxylate) ruthenium (II) bis (tetrabutylammonium), commercially available from Solaronix (Switzerland). Met. A solution of ruthenium 535 bis TBA is prepared by dissolving ruthenium 535 bis TBA in pure ethanol at a concentration of 0.5 mmol. After immersing the titanium oxide substrate in a solution of ruthenium 535 bis-TBA for 24 hours and removing from the solution, the titanium oxide substrate that has absorbed the dye is washed again with ethanol to remove the physically absorbed dye layer, and then The substrate was dried again at 60 ° C.

Example 3: Preparation of PVDF-HFP polymer solution for electrospinning Polyvinylidene fluoride-hexafluoropropylene was dissolved in a mixed solution of acetone and N, N-dimethylacetamide (mass ratio 7: 3) to obtain PVDF-HFP. A polymer solution was prepared. The mixture was stirred for 24 hours in a stirrer and sonicated for 30 minutes for complete dissolution.

Example 4: Preparation of Ag-containing PVDF-HFP polymer solution Polyvinylidene fluoride-hexafluoropropylene was dissolved in a mixed solution of acetone and N, N-dimethylacetamide (mass ratio 2: 1), followed by 1 to 20% by mass of Ag was added to prepare a PVDF-HFP polymer solution. The mixture was stirred for 24 hours in a stirrer and sonicated for 30 minutes for complete dissolution.

Example 5: Preparation of polyvinylidene fluoride of an inorganic nanofiller-containing PVDF-HFP polymer solution - a mixture of Al ₂ O ₃ and BaTiO ₃ were weighed individually as hexafluoropropylene and inorganic nanofillers, inorganic nanofiller A polymer solution containing was prepared. The amount of inorganic nanofiller used was 10-40% by weight based on the polymer used. This mixture was dissolved in a mixed solution of acetone and N, N-dimethylacetamide (mass ratio 7: 3). The mixture was stirred for 24 hours in a stirrer and sonicated for 30 minutes for complete dissolution.

Example 6: Preparation of PVA polymer solution for electrospinning PVA polymer solution was prepared by dissolving polyvinyl alcohol (PVA) in distilled water in an amount of 10 mass% with respect to distilled water. This solution was stirred in a stirrer at 80 ° C. for 6 hours, further stirred for 24 hours at a lower temperature, room temperature, completely dissolved in distilled water, and then sonicated for 1 hour.

Example 7: Preparation of Ag-containing PVA polymer solution Polyvinyl alcohol (PVA) was dissolved in distilled water in an amount of 10% by mass with respect to distilled water, Ag was added, and a PVA polymer solution containing Ag was prepared. Got ready. This solution was stirred in a stirrer at 80 ° C. for 6 hours, the temperature was lowered to room temperature, and polyvinyl alcohol was completely dissolved in distilled water. A few drops of nitric acid were added to the solution to avoid Ag reduction during stirring of the polymer solution formed by adding Ag in an amount of 0.01% by weight to the polymer. . This solution was further stirred for 24 hours in a stirrer and mixed well, and sonication was performed for 1 hour.

Example 8: Preparation of polymer mixed solution for electrospinning A polymer mixed solution was prepared by adding each of polystyrene and polymethyl methacrylate to polyvinylidene fluoride-hexafluoropropylene. The solvent used is DMF when PVDF-HFP and PS are mixed, but when PVDF-HFP and PMMA are mixed, acetone and N, N-dimethylacetamide (mass ratio 7: 3) are mixed. Dissolved in solution. This solution was stirred for 24 hours in a stirrer and subjected to ultrasonic treatment for 30 minutes to be completely dissolved.

Example 9: Preparation of PVDF-HFP polymer nanofibers by electrospinning Electrospinning was performed to obtain various nanoscale diameters by changing the polymer mass%, supply voltage, and spinning interval. The polymer dissolved in the solvent was introduced into the electrospinner at a constant rate in a solution transporter. In the experiment, the output rate was 2 ml / h. When the polymer was dissolved in the solvent, polymer nanofibers were produced by changing the amount of polymer between 11% and 17% by weight with respect to the solution. The amount of polymer is in a suitable range as mentioned in the structure of the present invention. Electrospinning was performed by changing the voltage from the voltage source between 8 kV and 14 kV. Electrospinning was performed by changing the spinning distance between 13 cm and 19 cm. Electrospinning polymer nanofibers were produced at optimal conditions of 15 wt%, 14 kV, and 15 cm.

Example 10: Preparation of Ag-containing PVDF-HFP polymer nanofibers by electrospinning Electrospinning was performed by changing the polymer mass%, supply voltage, and spinning interval to vary the diameter of PVDF containing Ag. -HFP nanofibers were obtained. Furthermore, polymer nanofibers were produced by changing the conditions by introducing 1% by mass to 20% by mass of Ag. In the experiment, the output rate from the solution transporter was 0.2 ml / h to 2.0 ml / h. Electrospinning was performed by changing the voltage from the voltage source between 8 kV and 20 kV. Electrospun nanofibers were produced by changing the spinning distance between 13 cm and 21 cm.

Example 11: Preparation of inorganic nanofiller-containing PVDF-HFP polymer nanofibers by electrospinning Electrospinning was performed by changing the polymer mass%, supply voltage, and spinning interval to achieve nanoscale inorganic nanofilling PVDF-HFP nanofibers of various diameters containing the material were obtained. Furthermore, polymer nanofibers were produced by changing the conditions by introducing 10% by mass to 40% by mass of inorganic nanofillers (Al ₂ O ₃ , BaTiO ₃ ). In the experiment, the output rate from the solution transporter was 1.5 ml / h. Electrospinning was performed by changing the voltage from the voltage source between 12 kV and 15 kV. Electrospun nanofibers were produced by changing the spinning distance between 15 cm and 18 cm.

Example 12: Preparation of polymer nanofibers by PVA electrospinning When preparing polyvinyl alcohol (PVA) fibers, electrospinning was performed by changing the polymer mass%, supply voltage, and spinning interval, as described above. So we got a nanoscale diameter. In the experiment, the output rate from the solution transporter was 0.6 ml / h. When the polymer was dissolved in the solvent, polymer nanofibers were produced by changing the amount of the polymer between 8% by mass and 10% by mass with respect to the solution. Fibers were produced by changing the voltage from the voltage source between 15 kV and 20 kV. Electrospinning was performed by changing the spinning distance between 15 cm and 22 cm. Polymer nanofibers were produced under optimal conditions of 9% by weight, 20 kV, and 20 cm.

Example 13: Preparation of polymer nanofibers using electrospinning of Ag-containing PVA When Ag-containing polyvinyl alcohol fibers were prepared, electrospinning was performed under the same conditions as in Example 7. An adapter made of graphite was used to avoid Ag reduction during electrospinning, but when performing electrospinning, an adapter made of stainless steel is typically used to connect the tip to the nozzle Is done. Finally, after spinning the Ag-containing fiber, it was pressed on a hot plate for 15 minutes to reduce Ag.

Example 14: Preparation of polymer nanofibers using electrospinning of mixed polymer After mixing PVDF-HFP and polystyrene, the experiment was conducted with a power supply from a solution transporter at a rate of 0.5 ml / h from a voltage source. The electrospinning was performed by changing the voltage of 13 kV to 20 kV. Electrospun polymer nanofibers were produced by changing the spinning distance between 15 cm and 23 cm. Polymer nanofibers were produced under optimal conditions of 15 wt%, 20 kV, and 23 cm.

Example 15: Analysis of surface and nanofiber distribution of PVDF-HFP polymer nanofibers using scanning electron microscopy FIGS. 6A and 6B are surface images and diameters of polymer fibers with 15 wt% polymer. FIG. Polymer nanofibers were produced by changing the polymer mass% at a supply voltage of 14 kV, a spinning distance of 15 cm, and a solution supply rate of 2 ml / h. As shown in FIGS. 6A and 6B, the obtained nanofibers were found to have the most uniform distribution with a diameter of 800 nm to 1000 nm.

Example 16: Analysis of surface and nanofiber distribution of Ag-containing PVDF-HFP polymer nanofibers using scanning electron microscopy FIGS. 7A-7L show the amount of Ag contained in the polymer is 0.3. It is the surface image of the polymer fiber by changing between 10 mass% and 10 mass%. Polymer nanofibers were produced by changing the mass% of Ag contained in the polymer at a supply voltage of 15 kV to 20 kV, a spinning interval of 15 cm to 20 cm, and a solution supply rate of 0.3 ml / h to 2 ml / h. As shown in FIGS. 7A to 7L, the obtained nanofibers were found to have the most uniform distribution with a diameter of 200 nm to 500 nm.

Example 17: Analysis of Surface and Nanofiber Distribution of Inorganic Nanofiller-Containing PVDF-HFP Polymer Nanofibers Using Scanning Electron Microscopy FIGS. 8A-8L are Al ₂ O as inorganic nanofillers. It is the surface image of the polymer fiber by changing the quantity of ₃ between 10 mass%-40 mass%. Polymer nanofibers were produced by changing the mass% of the inorganic nanofiller at a supply voltage of 12 kV, a spinning interval of 15 cm, and a solution supply rate of 1.5 ml / h. As shown in FIGS. 8A-8L, the resulting nanofibers had the best fiber morphology when 40 wt% Al ₂ O ₃ was added.

9A to 9L are surface images of polymer fibers obtained by changing the amount of BaTiO ₃ as an inorganic nanofiller between 10% by mass and 40% by mass. Polymer nanofibers were produced by changing the mass% of the inorganic nanofiller at a supply voltage of 12 kV, a spinning interval of 15 cm, and a solution supply rate of 1.5 ml / h. As shown in FIGS. 9A to 9L, the obtained nanofibers were shown to have an agglomerated shape and the most uniform distribution with diameters of 500 nm to 1000 nm.

Example 18: Analysis of surface and nanofiber distribution of PVA polymer nanofibers using scanning electron microscopy FIGS. 10A and 10B are surface images and distribution maps of the diameter of PVA polymer fibers. When the image polymer fiber was electrospun, the supply voltage was 20 kV, the spinning interval was 20 cm, and the solution supply rate was 0.6 ml / h. As shown in FIG. 10B, the obtained nanofibers were shown to have the most uniform distribution with a diameter of 180 nm to 200 nm.

Example 19: Analysis of Ag-containing PVA polymer nanofiber surface and nanofiber distribution using scanning electron microscopy FIG. 11 is a surface image of an Ag-containing PVA polymer fiber. When the image polymer fiber was electrospun, the supply voltage was 20 kV, the spinning interval was 20 cm, and the solution supply rate was 0.6 ml / h. The Ag-containing PVA polymer fiber had a diameter in the same range as the polymer containing no Ag. Although Ag was contained in the PVA fiber, it was revealed that the original form was unchanged.

Example 20: Analysis of Mixed Polymer Nanofiber Surface and Nanofiber Distribution Using Scanning Electron Microscopy FIGS. 12A-12C show surface images of PVDF-HFP and polystyrene mixed polymer nanofibers. When the polymer fiber of the image was electrospun, the supply voltage was 20 kV, the spinning interval was 21 cm, and the solution supply rate was 5.0 ml / h. The diameter of the PVDF-HFP and polystyrene mixed polymer nanofibers was about 1000 nm thicker than the unmixed PVDF-HFP nanofibers, and the strand shape was bumpy.

  13A-13C show surface images of mixed polymer nanofibers of PVDF-HFP and PMMA. When the polymer fiber of the image was electrospun, the supply voltage was 20 kV, the spinning interval was 21 cm, and the solution supply rate was 4.0 ml / h. The diameter of the PVDF-HFP and PMMA mixed polymer nanofibers had a similar range of diameters of about 600 nm as the unmixed PVDF-HFP nanofibers, and the shape of both strands was substantially similar.

Example 21: Preparation of electrolyte solution Tetrabutylammonium iodide 0.2 mol, iodine 0.05 mol and 1-propyl-3-methylimidazolium iodide 0.3 mol were mixed with ethylene carbonate, polypropylene carbonate, and acetonitrile (volume). An electrolyte solution was prepared by mixing in a solvent of ratio 8: 2: 5) and then stirred for 24 hours.

  In an example of a dye-sensitized solar cell prepared by using polyvinyl alcohol fiber, 0.02 mol of tetrabutylammonium iodide, 0.08 mol of iodine, and 0.03 mol of 1-propyl-3-methylimidazolium iodide Were mixed in a solvent of ethylene carbonate, polypropylene carbonate, and acetonitrile (volume ratio 8: 2: 5) to prepare an electrolyte solution, and then stirred for 24 hours.

Example 22: Creation of an electrolyte layer using polymer nanofibers Polymer nanofibers prepared according to Examples 6-8 were placed on a substrate of titanium oxide that had absorbed the dye of Example 2, and then By using a micropipette, 0.035 mol of electrolyte solution was dropped onto the top of the substrate. Then, it was dried at 40 ° C. to 50 ° C. for 2 hours to 3 hours in an oven to evaporate the solvent.

Example 23: Preparation of Pt electrode A transparent dye-sensitized solar cell was prepared using a paste containing a Pt precursor. Pastes containing Pt precursors are commercially available from Solaronix (Switzerland).

  By using a paste containing a Pt precursor raised from room temperature to 400 ° C., Pt was deposited on an FTO glass substrate cut into a size of 15 mm × 10 mm in the same manner as the titanium oxide layer of Example 1. Applied. Using the alpha step, the resulting Pt electrode was measured and the thickness was determined to be about 100 nm.

Example 24 Production of Solid Type Dye-Sensitized Solar Cell Element Electrode Substrate Containing Polymer Fiber and Electrolyte Coated on Titanium Oxide Layer Absorbing Dye According to Example 22 and Pt Electrode Prepared According to Example 23 A dye-sensitized solar cell element was prepared by element bonding with the substrate.

Example 25: Measurement of electro-optical properties of dye-sensitized solar cell element Electro-optical properties of a dye-sensitized solar cell produced according to Example 24. The voltage-current density of the dye-sensitized solar cell having the electrolyte containing the polymer fiber according to Example 22 was measured under the standard conditions (AM1.5, 100 mW / cm ² , 25 ° C.), and the solar simulator (PEC-L11, PECCELL) was used. Measured by use. The solar simulator was modified by installing a 150W xenon lamp and Keithley and using a standard silicon battery.

Results of electro-optical properties FIGS. 14 to 19 show current and voltage graphs based on the measurement results of the electro-optical properties of the dye-sensitized solar cell element, respectively.
FIG. 14 is a graph showing the voltage-current density of a dye-sensitized solar cell element at 100 mW / cm ² illumination condition using a PVDF-HFP fiber having a nanoscale diameter produced according to Example 9. . According to FIG. 14, the current density increased when the interface bonding layer and the scattering layer were introduced.
FIG. 15 is a graph showing the voltage-current density of a dye-sensitized solar cell element in the dark state using PVDF-HFP fibers having a nano-scale diameter manufactured according to Example 9. It was found that when the interface bonding layer and the scattering layer were introduced, the voltage increased because these two layers prevented recombination of the TiO ₂ layer and the electrode layer.

  Table 1 shows the dye-sensitized solar prepared by adding PVDF-HFP polymer fibers manufactured under the conditions that the supply voltage is 14 kV, the spinning interval is 15 cm, the solution supply speed is 2 ml / h, and the polymer mass% is changed. The property of a battery element is shown. It was found that when the interface junction layer and the scattering layer were introduced, the current density increased significantly while the open circuit voltage and fill factor did not vary much. Therefore, the overall energy conversion efficiency was improved by 60%, and a dye-sensitized solar cell having a high efficiency of 8.58% could be manufactured.

[Table 1]
Comparison of photovoltaic performance of dye-sensitized solar cell elements using PVDF-HFP polymer nanofibers in inorganic oxide layer with interfacial bonding layer and scattering layer introduced

  Table 2 shows that an Ag-containing PVDF-manufactured under conditions in which the supply voltage is 8 kV to 20 kV, the spinning interval is 13 cm to 21 cm, the required supply rate is 0.2 ml / h to 2 ml / h, and the mass% of Ag to the polymer is changed The property of the dye-sensitized solar cell element produced by adding HFP polymer fiber is shown. When 1/100 mass% Ag was added, it became clear that a current density increased significantly.

[Table 2]
Comparison of photovoltaic performance of dye-sensitized solar cell elements using Ag-containing PVDF-HFP polymer nanofibers

FIG. 16 is a graph showing the voltage-current density of a dye-sensitized solar cell element in a 100 mW / cm ² illumination state using a PVDF-HFP fiber having a nanoscale diameter produced according to Example 11; -HFP is containing Al ₂ O ₃ as the inorganic nanofiller.

Table 3 is a condition in which the supply voltage is 12 kV to 15 kV, the spinning interval is 15 cm to 18 cm, the solution supply rate is 1.5 ml / h, and the mass% of the polymer of Al ₂ O ₃ as the inorganic nanofiller is changed. The property of the dye-sensitized solar cell element produced by adding the manufactured inorganic nanofiller containing PVDF-HFP polymer nanofiber is shown.
According to FIG. 16 and Table 3, the short circuit current has a maximum value when the content of Al ₂ O ₃ added to PVDF-HFP is 20% by mass to 30% by mass, and the energy conversion efficiency is It has a maximum value in the case of 30% by mass.

FIG. 17 is a graph showing the voltage-current density of a dye-sensitized solar cell element using a PVDF-HFP fiber having a nanoscale diameter produced according to Example 11 in an illumination state of 100 mW / cm ² ; PVDF-HFP contains BaTiO ₃ as an inorganic nanofiller.

[Table 3]
Comparison of photovoltaic performances of the dye-sensitized solar cell element using the PVDF-HFP polymer nanofiber containing Al ₂ O ₃ as the inorganic nanofiller

Table 4 shows the properties of the dye-sensitized solar cell element prepared under the same conditions as in Table 3 when BaTiO ₃ is used instead of Al ₂ O ₃ .
According to FIG. 17 and Table 4, the current density and the energy conversion efficiency have maximum values when the content of BaTiO ₃ added to PVDF-HFP is 20 mass%.

[Table 4]
Comparison of photovoltaic performance of dye-sensitized solar cell elements using PVDF-HFP polymer nanofibers containing BaTiO ₃ as inorganic nanofillers

According to Tables 2 to 4, the current density and energy conversion efficiency were determined by inserting fibers containing Ag, Al ₂ O ₃ , or BaTiO ₃ as inorganic nanofillers into a dye-sensitized solar cell and melting in the electrolyte. When it was made, it improved largely compared with the dye-sensitized solar cell which has the fiber which does not contain those components.

FIG. 18 is a graph showing the voltage-current density of a dye-sensitized solar cell using a PVA fiber having a nanoscale diameter produced according to Example 12 and in an illumination state of 100 mW / cm ² . As can be seen from FIG. 18, the voltage increases when the interface bonding layer and the scattering layer are introduced.
FIG. 19 is a graph showing the voltage-current density of a dye-sensitized solar cell element in the dark state using a PVA fiber having a nanoscale diameter produced according to Example 12. When the interface bonding layer and the scattering layer were introduced, it became clear that these two layers prevented recombination between the TiO ₂ layer and the electrode layer, and thus the voltage increased.

  Table 5 shows dye sensitization prepared by adding PVA polymer fibers manufactured under the conditions that the supply voltage was 20 kV, the spinning interval was 20 cm, the solution supply rate was 0.6 ml / h, and the polymer mass% was changed. The property of a solar cell element is shown. According to Table 5, the current density increased significantly when the interfacial bonding layer and the scattering layer were introduced, while the open circuit voltage and fill factor did not vary much. Therefore, when the total energy conversion efficiency is specified, a dye-sensitized solar cell having a high efficiency of 7.36% can be manufactured.

[Table 5]
Comparison of photovoltaic performance of dye-sensitized solar cell elements using PVA polymer nanofibers in inorganic oxide layer with interfacial bonding layer and scattering layer introduced

FIG. 20 is a graph showing the voltage-current density of a dye-sensitized solar cell element in an illumination state of 100 mW / cm ² using a PVA fiber having a nanoscale diameter produced according to Example 13, where PVA is Contains Ag.

  Table 6 shows the property of the dye-sensitized solar cell element prepared by adding Ag-PVA fiber manufactured on the same conditions as manufacture of PVA. According to Table 6, the energy conversion efficiency was improved to 8.12% by adding Ag to the PVA fiber.

[Table 6]
Comparison of photovoltaic performance of dye-sensitized solar cell elements using polymer nanofibers (Ag-PVA) in an inorganic oxide layer with an interface bonding layer and a scattering layer introduced

In experiments using PVA fibers, the current density was measured when the Ag-containing fibers were inserted into a dye-sensitized solar cell and melted in the electrolyte (Table 6). Compared with (Table 5), it was greatly improved. This is a result of Ag functioning as a medium to help move ions within the electrolyte, thereby increasing ionic conductivity between the TiO ₂ , electrolyte, and Pt electrodes.

  Table 7 shows a dye-sensitized solar cell element prepared by adding a PVDF-HFP / polystyrene mixed polymer fiber manufactured under the conditions of a supply voltage of 20 kV, a spinning interval of 21 cm, and a solution supply speed of 5.0 ml / h. Of a dye-sensitized solar cell element prepared by adding a mixed polymer fiber of PVDF-HFP and PMMA manufactured under the conditions of a supply voltage of 20 kV, a spinning interval of 20 cm, and a solution supply rate of 4.0 ml / h Indicates.

[Table 7]
Comparison of photovoltaic performance of dye-sensitized solar cell elements using mixed polymer PVDF-HFP with polystyrene and PMMA respectively

Example 26: Measurement of impedance of dye-sensitized solar cell element The resistance at each interface was measured by measuring the impedance of the dye-sensitized solar cell element produced according to Example 15. FIGS. 21-27 are graphs showing impedance data obtained by measuring values using an Echem Analyst (GAMRY) and fitting to Z-MAN software.

  FIG. 21 is a Bode diagram of the impedance of a dye-sensitized solar cell element having an interface bonding layer and a light scattering layer introduced into an inorganic oxide layer and an element not having these two layers. Since the peak in the figure is near the low frequency, the charge moves faster and the lifetime of the electrons is longer. When interfacial bonding layers and light scattering layers are introduced, the peak of the figure is shifted closer to low frequencies, so that the fast movement of charge provides a high field density and energy conversion efficiency, so that the surface bonding layer And by introducing a light scattering layer.

Tables 8 and 9 show a dye-sensitized solar cell element prepared using PVDF-HFP nanofibers and PVA nanofibers by electrospinning after introducing an interface bonding layer and a light scattering layer into the inorganic oxide layer, and The result of having measured the resistance of the dye-sensitized solar cell element produced using the polymer thin film by a spin coat method is shown. Rs is the series resistance of the solar cell element, R1 _CT is the resistance between the inorganic oxide layer (1003) including the interface bonding layer I (1004) and the light scattering layer (1005), and R2 _CT is The resistance between the light scattering layer (1005) including the interface bonding layer II (1006) and the polymer electrolyte layer (1008), and R3 _CT is the resistance between the polymer electrolyte layer (1008) and the second electrode (1009). Resistance between. Although there is no significant difference between R _1CT , R2 _CT , and R3 _CT , the value of R2 _CT indicated that the resistance of the dye-sensitized solar cell element made using polymer nanofibers was lower. Therefore, a low current resistance between the light scattering layer and the electrolyte layer provides a high current density as photovoltaic performance.

  22 and 24 are impedance Bode diagrams, and FIGS. 23 and 25 are Nyquist diagrams. Since the Bode diagram peaks are at the same frequency in the low frequency region, there is no significant difference in charge transfer. The larger and higher semicircle in the figure means that there are many recombination of electrons and doped holes. When polymer thin films are used by spin coating, the semicircle in the figure in the high frequency region is larger, thereby causing more recombination. Therefore, high and low resistance can be obtained as photovoltaic performance.

  FIG. 26 is a comparison of impedance Bode plots of dye-sensitized solar cell elements made using Ag-containing PVA fibers with nanoscale diameters according to the examples. Since the peaks in the two figures are at the same frequency, there is no significant difference in charge transfer. FIG. 27 is a comparison of impedance Nyquist diagrams for dye-sensitized solar cell elements made using Ag-containing PVA fibers with nanoscale diameters according to the examples. However, because the curves in the two figures showed similar patterns, the interfacial resistance of PVA was lower than that of Ag-PVA and generally showed a lower resistance.

[Table 8]
Resistance from measurement of impedance of dye-sensitized solar cell element made using PVDF-HFP nanofibers by electrospinning method and dye-sensitized solar cell element made using PVDF-HFP polymer thin film by spin coating method level

[Table 9]
Resistance levels from measurement of impedance of dye-sensitized solar cell elements prepared using PVA nanofibers by electrospinning method and dye-sensitized solar cell elements prepared using PVA polymer thin film by spin coating method

As described above, the dye-sensitized solar cell prepared by using the Ag-containing fiber has an increased current density due to an increase in ion conductivity between the interfaces. This can be confirmed from an impedance analysis. Although there is no significant difference between the series of resistances of the solar cell elements, the values of R1 _CT , R2 _CT , and R3 _CT for solar cells made using Ag-containing nanofibers decreased. Therefore, it turned out that the resistance between the interfaces of the solar cell produced using Ag containing nanofiber fell.

FIG. 28 is a comparison of the impedance Bode plots of dye-sensitized solar cell elements made using PVDF fibers having nanoscale diameters according to the examples. PVDF uses Al ₂ O ₃ as an inorganic nanofiller. contains. Since the peaks in the two figures are at similar frequencies, there is no significant difference in charge transfer. FIG. 29 is a comparison of the Nyquist diagram of the impedance of a dye-sensitized solar cell element made using PVDF fibers having a nanoscale diameter according to an example. PVDF uses Al ₂ O ₃ as an inorganic nanofiller. contains. Figure of PVDF-HFP fibers containing inorganic nanofillers Al ₂ O ₃ has a smaller semicircular than fibers not containing inorganic nanofillers Al ₂ O _3, whereby the inorganic nanofiller Al ₂ O ₃ The introduction of has been shown to prevent recombination.

[Table 10]
As the inorganic nanofiller containing Al ₂ O _3, the resistance level from the measurement of the impedance of the dye-sensitized solar cell prepared using the PVDF-HFP nanofiber by electrospinning method

Example 27: Electrolyte Durability Test of PVDF-HFP Polymer Nanofibers Made by Electrospinning Method A polymer fiber was prepared by electrospinning PVDF-HFP, and then the resulting polymer fiber was placed between glass substrates. The electrolyte is also introduced. A durability test was performed.
FIG. 30A is an image after the glass substrate is bonded without introducing the polymer fiber and then only the electrolyte is introduced. (A-1) in FIG. 30 is an image after the fibers are introduced, the glass substrate is joined, and then the electrolyte is introduced. After making a hole with a diameter of 1 mm through the glass substrate, an electrolyte was introduced through the hole and observed for 48 hours without filling the hole.
FIG. 30B is an image 12 hours after joining the glass substrate and then introducing only the electrolyte. (B-1) in FIG. 30 is an image 12 hours after the fiber is introduced, the glass substrate is joined, and then the electrolyte is introduced.
FIG. 30C is an image 36 hours after joining the glass substrate and then introducing only the electrolyte. (C-1) in FIG. 30 is an image 36 hours after the fiber is introduced, the glass substrate is joined, and then the electrolyte is introduced.
FIG. 30D is an image 48 hours after joining the glass substrate and then introducing only the electrolyte. (D-1) in FIG. 30 is an image 48 hours after the fiber is introduced, the glass substrate is joined, and then the electrolyte is introduced. Comparing the images after 48 hours, the amount of the electrolyte in FIG. 30 (D) in which only the electrolyte was introduced was reduced by evaporation, while that in FIG. 30 (D) in which the fibers and the electrolyte were introduced. There is almost no evaporation of the electrolyte, and the electrolyte is held in the glass substrate. It is shown that the polymer nanofiber can stably hold the electrolyte in the glass substrate. (E) of FIG. 30 is a photograph in which the glass substrate is removed to check whether or not the fiber is retained in the electrolyte after 48 hours. It can be seen that the fibers are retained without melting or scattering even after 48 hours.

Comparative Example 1: Photovoltaic performance of a dye-sensitized solar cell using a spin-coated PVDF-HFP polymer as an electrolyte substrate A polymer thin film was prepared by spin coating using a polymer PVDF-HFP, and then The resulting thin film is introduced into a dye-sensitized solar cell, and then the photovoltaic performance of the device is measured.

  A dye-sensitized solar cell is prepared according to the same process and conditions as in the Examples except that an electrolyte solution is prepared and a polymer thin film by spin coating is used instead of polymer nanofibers. Regarding the dye-sensitized solar cell including the polymer thin film by the spin coating method, the current density was measured according to the voltage under the same conditions as in Example 25. The measurement of the voltage-current density of the dye-sensitized solar cell according to Comparative Example 1 is shown in FIG. 31, and Table 11 shows the open circuit voltage, the short circuit current, the fill factor, and the energy conversion efficiency.

  In the dye-sensitized solar cell according to Comparative Example 1, the open circuit voltage specified by the difference in the band cap energy of the electrodes is the same as in Example 9 in which the polymer nanofibers are included. However, for devices containing typical polymer fibers, the value of the short circuit current was lower. This is thought to be due to the higher ion mobility due to the many pores in the polymer nanofibers. The energy conversion efficiency of Comparative Example 1 also has a tendency to be lower than that of a device including polymer nanofibers.

[Table 11]
Photovoltaic performance of dye-sensitized solar cells using PVDF-HFP polymer spin coated as electrolyte substrate

Comparative Example 2: Photovoltaic performance of a dye-sensitized solar cell using a spin-coated PVA polymer as an electrolyte substrate A polymer thin film was prepared by spin coating using the PVA polymer used in Example 6 Next, the produced thin film is introduced into a dye-sensitized solar cell, and then the photovoltaic performance of the device is measured.
A dye-sensitized solar cell is prepared according to the same process and conditions as in the Examples except that an electrolyte solution is prepared and a polymer thin film by spin coating is used instead of polymer nanofibers. Regarding the dye-sensitized solar cell including the polymer thin film by the spin coating method, the current density was measured according to the voltage under the same conditions as in Example 25. The measurement of the voltage-current density of the dye-sensitized solar cell according to Comparative Example 2 is shown in FIG. 32, and Table 12 shows the open circuit voltage, the short circuit current, the fill factor, and the energy conversion efficiency.

  In the dye-sensitized solar cell according to Comparative Example 2, the open circuit voltage specified by the difference in the band cap energy of the electrode is the same as that of Example 15 in which the polymer nanofiber is included. However, for devices containing typical polymer fibers, the value of the short circuit current was lower. This is thought to be due to the higher ion mobility due to the many pores in the polymer nanofibers. The energy conversion efficiency of Comparative Example 2 also has a tendency to be lower than that of a device including polymer nanofibers.

[Table 12]
Photovoltaic performance of dye-sensitized solar cells using spin-coated PVA polymer as electrolyte substrate

Comparative Example 3: Photovoltaic Performance of Dye-Sensitized Solar Cell Using Liquid Electrolyte Dye-sensitized with only liquid electrolyte introduced to find and compare the energy conversion efficiency of dye-sensitized solar cells without polymer fibers Prepare solar cells.
The current density is measured according to the voltage determined under the same conditions as in Example 25. FIG. 33 shows the measurement of the voltage-current density of the dye-sensitized solar cell according to Comparative Example 3, and Table 13 shows the open circuit voltage, the short circuit current, the fill factor, and the energy conversion efficiency.
Table 14 shows impedance values according to Comparative Example 3. According to Table 14, the overall impedance value is reduced. Therefore, it can be seen that the internal resistance is increased by the nanofibers, and therefore, when only the electrolyte is used without the nanofibers, the overall resistance is reduced.

[Table 13]
Photovoltaic performance of dye-sensitized solar cells using liquid electrolytes

[Table 14]
Measuring the impedance of dye-sensitized solar cells using liquid electrolytes

  A preferred embodiment, which is exemplary only, will be described and various modifications and variations of the invention may be implemented. However, it will be apparent that such changes and modifications are encompassed within the scope of the invention without departing from the scope of the appended claims of the invention.

1001: first substrate 1002: first electrode 1003: inorganic oxide layer 1004: interface bonding layer I
1005: Light scattering layer 1006: Interfacial bonding layer II
1007: Dye layer 1008: Polymer electrolyte layer 1009: Second electrode 1010: Second substrate 2001: Voltage supply source 2002: Solution transporter 2003: Electrospinner 2004: Collector

Claims (21)

A first substrate and a second substrate arranged to face each other;
A first electrode disposed between the first substrate and the second substrate, which is chemically absorbed in the inorganic oxide layer and the inorganic oxide layer to provide excited electrons. A first electrode including a dye layer;
A second electrode disposed opposite to the first electrode, the second electrode disposed between the first substrate and the second substrate, thereby allowing a current to flow; Electrodes,
A first interface bonding layer configured to facilitate interfacial bonding of the inorganic oxide layer onto the inorganic oxide layer;
A second interface bonding layer configured to avoid reverse current on the first interface bonding layer;
A light scattering layer disposed between the first interface bonding layer and the second interface bonding layer to increase absorption;
A solid electrolyte disposed between the first electrode and the second electrode, comprising a polymer nanofiber manufactured by an electrospinning method, and providing electrons to the dye layer by a redox reaction A dye-sensitized solar cell comprising an electrolyte.   The polymer fibers include polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), and polymer mixtures thereof. The dye-sensitized solar cell according to claim 1, which is at least one selected from the group consisting of:   The dye-sensitized solar cell according to claim 1, wherein a content of the polymer is 5 mass percent to 95 mass percent with respect to the solid electrolyte.   The dye-sensitized solar cell according to claim 1, wherein the polymer has a weight average molecular weight of 50,000 to 1,000,000.   The dye-sensitized solar cell according to claim 1, wherein the polymer fiber has a diameter of 20 nm to 1500 nm.   The dye-sensitized solar cell according to claim 1, wherein the solid electrolyte contains nano-sized Ag.   The dye-sensitized solar cell according to claim 1, wherein the solid electrolyte further includes an inorganic nanofiller. The dye-sensitized solar cell according to claim 7, wherein the inorganic nanofiller is Al ₂ O ₃ or BaTiO ₃ .   The dye-sensitized solar cell according to claim 1, wherein the first and second interface bonding layers have a thickness of 10 nm to 100 nm.   The particle | grains which form the said light-scattering layer are dye-sensitized solar cells of Claim 1 which have a particle size of 100 nm-500 nm.   2. The dye-sensitized solar cell according to claim 1, wherein the dye layer is at least one selected from the group consisting of a ruthenium dye, a xanthan dye, a cyanine dye, a porphyrin dye, and an anthraquinone dye. A method for preparing a dye-sensitized solar cell, comprising:
Preparing a first substrate;
Forming an inorganic oxide layer on one surface of the first substrate to form a first electrode;
Forming a first interface bonding layer that facilitates interface bonding of the inorganic oxide layer onto the inorganic oxide layer;
Forming a light scattering layer on the first interface bonding layer to increase absorption;
Forming a second interface bonding layer on the light scattering layer to avoid reverse current;
Absorbing a dye layer on the second interfacial bonding layer;
Polymer nanofibers produced by electrospinning a polymer solution using an electrospinning apparatus are formed on the second interface bonding layer that has absorbed the dye layer, and an electrolyte solution is applied to the polymer nanofibers. And then evaporating the applied solution to form a solid electrolyte, and forming a second electrode and a second substrate on the solid electrolyte.   13. The step of forming the solid electrolyte comprises dissolving a polymer in a solvent to form a polymer solution, introducing the formed polymer solution into an electrospinner, and spinning the polymer solution. The method described.   The method of claim 12, wherein the polymer solution comprises nano-sized Ag in the step of forming the solid electrolyte.   The method of claim 12, wherein the polymer solution further comprises an inorganic nanofiller in the step of forming the solid electrolyte. The method of claim 15, wherein the inorganic nanofiller is Al ₂ O ₃ or BaTiO ₃ .   The electrospinning apparatus uses a voltage supply source that applies a voltage to form nanofibers, a solution transporter that periodically sprays the polymer solution, and a voltage applied from the voltage supply source. The method of claim 12, comprising: an electrospinner that produces polymer nanofibers from the polymer solution conveyed from the solution transporter; and a collector that collects the nanofibers spun from the electrospinner.   The method of claim 12, wherein the electrospinner controls the spinning interval.   The polymer is selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polyvinyl alcohol (PVA). 13. The method of claim 12, wherein there is at least one.   The method of claim 12, wherein the first and second interface bonding layers have a thickness of 10 nm to 100 nm.   The method according to claim 12, wherein the particles forming the light scattering layer have a particle size of 100 nm to 500 nm.

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